Quantitative generation of dynamic optical turbulence environment for offshore laser communication

A method for generating diverse dynamic turbulence-distorted images is proposed to enable visual evaluation of turbulence effects in long-range maritime optical communication. Firstly, a spatial correlation characterization model for pixel displacement is established to represent image tilt distortion caused by low-frequency turbulence components. Subsequently, the point spread function (PSF) is analytically derived from turbulence intensity parameters, which incorporate both turbulence-induced high-frequency blur components and residual low-frequency components. Then, a non-uniform blocking method is applied to the tilt-distorted image, where smaller block sizes are employed in edge regions compared to the central area to address insufficient tilt distortion at image edges caused by decreasing pixel correlation with increasing distance. Finally, the PSF of each local region is convolved with the corresponding area of the tilted image to simulate the random and non-uniform evolution characteristics of turbulence disturbances. Additionally, several aspects such as the spatial correlation of pixel displacement, the phase structure function, long-exposure and short-exposure PSFs, and the simulator's runtime are analyzed. In terms of computational efficiency, the generation of a 256 × 256 pixel image requires only 0.414 s. Regarding simulation accuracy under an atmospheric coherence length of 0.1 m, the non-uniform blocking method reduces the root mean square error (RMSE) of the fitted long-exposure PSF by 78.56% compared with the uniform blocking methods. This work provides a technical approach for evaluating turbulence effects.